Profile recovery for LAMOST fiber spectral data with low SNR via improved time-frequency peak filtering

A new profile recovery method which is called time–frequency peak filtering (TFPF) is introduced to low signal-to-noise ratio (SNR) astronomical fiber spectral signals. TFPF is an effective noise removal method, which is essentially instantaneous frequency (IF) estimation based on Wigner–Ville distribution (WVD). To achieve a better noise suppression result of spectral signal, we propose an improved TFPF, which combines the pseudo WVD (PWVD) and the smoothed pseudo WVD (SPWVD). The proposed method produces a data fusion from the outcomes of PWVD and SPWVD to sharpen the time–frequency distribution and adopts a sine function to eliminate interference points in time–frequency domain. We test our method on both simulated and observed data based on the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) project. The results show good performance of the proposed method.